Adenovirus-2 late messenger RNA species labelled with 32p 14-17 hours post infection will be fractionated by hybridization to restriction fragments or by gel electrophoresis. Messenger RNA 3' and 5' terminal regions will be prepared and compared by T-1 ribonuclease fingerprinting and then will be located on the physical map of the genome. DNA sequencing will determine the structure of mRNA termini and adjacent regions of the DNA.